A number of potential problems are typically associated with roofs and roofing. Many result from rain water or melted ice or snow gaining access to building areas under covering shingles, fascia boards, trim pieces, and the like. It is quite common in winter, for example, for eavestroughs to become blocked by ice or other obstructions and for water, having no other drain course available, to find its way under shingles covering roof eaves. It is also common for water running over the actual roof edge to find its way up under shingles. At very least, it wets the fascia board and may find its way behind it.
Once access is gained to roof sheathing or beneath fascia or other trim pieces, water can advance to cause damage in a number of areas within the building, even areas seemingly remote from the leak site. In time, areas repeatedly saturated with water can suffer damage from mildew and rot. If undetected or not repaired, the physical integrity of the structure may eventually be threatened.
Another potential problem is associated with applying shingles to a roof. A starter strip is usually installed along the roof edge before any shingles are affixed. The starter is sometimes formed of a section of rolled roofing material but is often made by trimming the tabs off roofing shingles at the site. Under the pressure of completing a job, the shingles may not be trimmed squarely, allowing small areas of sheathing to be exposed to the weather. Even if the sheathing is completely covered, if the starter material is not applied properly, the subsequently applied shingles aligned therewith may be skewed.
Another common problem involves eavestroughs becoming clogged with objects such as nests, leaves falling from trees; rocks, balls and other toys rolling or washing into the trough after being thrown onto a roof by children; and nuts and twigs rolling or washing into the trough after being dropped onto a roof by squirrels and birds. Guards for eavestrough drains and screens for covering the open tops of eavestroughs are well known in the art, but they each have their own attending problems. Drain guards have a tendency, in time, to corrode and drop into the very drains they were installed to protect, thereby becoming effective clogging elements themselves. Many screens become dislodged and thereafter fail to prevent the passage of undesirable articles into eavestroughs. Some screens can be bent and formed around associated eavestroughs in an attempt to affix them thereto, but installing them is a less-than-precise procedure, and gaps in their coverage commonly result.